EP1895090B1 - Method and apparatus for creating a borehole in the ground - Google Patents

Abstract

The method involves setting a rotatably driven drill pipe (1) and a conveyor screw (2) into rotation, and introducing the drill pipe and the screw into soil. An outcropping soil material is loosened by a set of main cutting edges (50, 50`) positioned axially in front of the conveyor screw, and is conveyed away by the conveyor screw inside the drill pipe. The main cutting edges are arranged in the drill pipe and are rotated with the drill pipe. The drill pipe and the conveyor screw are controlled independently of each other with regard to rotational speed and/or direction of rotation. An independent claim is also included for a device for producing a borehole in soil.

Description

The invention relates to a method for creating a bore in the ground according to the preamble of claim 1. In such a method it is provided that a drill pipe and a screw conveyor, which is arranged in the interior of the drill pipe, are rotated and introduced into the ground, and existing soil material by means of at least one main cutting edge, which is upstream of the screw conveyor, is released, and is conveyed away by means of the screw conveyor inside the drill pipe.

The invention further relates to a device for making a bore in the ground according to the preamble of claim 5, comprising a drill pipe, a screw conveyor which is arranged in the interior of the drill pipe, and at least one main cutting edge, which is axially upstream of the screw conveyor for processing soil material.

The holes can be used in particular for the creation of foundation elements and / or pile walls.

Methods and apparatus for cased bores in the ground, in particular dual head methods or devices, are known. In this method, a drill pipe and a lying inside the drill pipe, in particular continuous screw simultaneously sunk down into the ground. The worm has at least in its end region a main cutting edge, which dissolves the pending in cross-section of the screw bottom and transported to the helix of the screw. From the main cutting edge, the soil material is conveyed upwards along the rotating screw. This conveying movement is due to frictional effects between the soil material and the surface of the screw flight and between the soil material and the inner wall of the drill pipe.

Such a method is for example from the EP 1 394 351 B1 known. It is particularly suitable for use in hilly soils, such as gravel and sand, in cohesive mixed soils and / or in soils that are below the groundwater level, since the production of an artificial water load can be avoided here.

However, it has been found that under certain circumstances, only a comparatively low rate of drilling progress can be achieved in the double-head drilling, which is often accompanied by a relatively high wear on the inner wall of the drill pipe and on the screw conveyor. This effect can occur in particular in poorly graded soil grains and / or in the presence of coarse gravel.

From the US-A-3,565,190 , of the DE 103 59 103 A1 , of the FR-A-2 832 438 or the JP 2001003363 A Go forth known methods and apparatus for creating a bore with a drill pipe and a conveyor screw arranged therein. At the lower end of the drill pipe, a cutting bit is provided. At the bottom End of the screw conveyor is a cutting device which extends radially and serves as the main cutting edge.

The object of the invention is to provide a method and apparatus for creating a hole in the ground, which are particularly versatile at comparatively low wear and high drilling progress.

The object is achieved by a method with the features of claim 1 and an apparatus having the features of claim 5. Preferred embodiments are given in the respective dependent claims.

The inventive method is characterized in that the main cutting edge is arranged on the drill pipe and is rotated with this.

The invention recognizes that in drilling methods and drilling devices of the prior art, in which the main cutting edge is arranged on the screw conveyor, the screw conveyor plays both the task of detaching the pending soil and of discharging the dissolved soil. However, this configuration is not optimal for all operating conditions. For example, in certain soil geologies, the force required to loosen the soil can be comparatively high, so that the main cutting edge and thus the conveying screw can only be rotated comparatively slowly. Under certain circumstances, this slow rotational speed may again be too low for a rapid discharge of the material. In this case, the material accumulates in the lower part of the screw. In particular, coarse grains can repeatedly roll down and clamp between the screw and Bohrrohrwandung. This can result in comparatively high rotational resistances, a comparatively high expenditure of force, a comparatively low penetration speed and a comparatively high degree of wear.

In contrast, the invention is based on the idea to free the screw conveyor at least partially from the task of solving the upcoming soil. Accordingly, the main cutting edge, which is provided for working off in the cross section of the conveyor screw pending soil material, according to the invention is not arranged on the screw conveyor, but rotatably provided relative to the auger on the drill pipe. The speed of the screw conveyor, and thus the delivery rate, and the speed of the main cutting edge, and thus the cutting performance, can therefore according to the invention relative to each other free be varied. In particular, the delivery rate of the screw conveyor can be adapted individually to the currently given removal rate of the main cutting edge even with changing soil geologies, so that an undesired material accumulation in the lower region of the screw conveyor can be effectively counteracted. The outgoing of such a backwater wear can thus be effectively reduced with good drilling progress. In addition, the invention makes it possible to react flexibly to changing soil geologies without the need for a complex conversion of the screw conveyor or other components of the device used.

According to the invention, the rotational speed of the drill pipe determines the rotational speed of the main cutting edge. For this purpose, the main cutting edge can be arranged rotatably on the drill pipe. But it is also possible, for example, to provide the main cutting edge within certain limits rotatable on the drill pipe.

According to the invention, it is advantageous for the drill pipe and the screw conveyor to be controlled independently of one another in terms of rotational speed and / or direction of rotation, as a result of which a particularly versatile method is provided. For this purpose, the drill pipe and the screw conveyor may for example have separate drive motors. However, it can also be provided at least one common drive motor which drives both the drill pipe and the auger via an adjusting gear. The adjusting mechanism, which may in particular be designed as a torque converter, may for example be infinitely adjustable, but also designed as a gear transmission.

For a particularly simple construction, the main cutting edge may be formed, for example, as a cutting edge. The main cutting edge can also be arranged by several juxtaposed Cutting tools such as flat teeth, round shank chisel and / or studs may be formed, in particular on a tool holder or directly attached to the drill pipe, in particular screwed, welded and / or gebolzt, may be. Preferably, the main cutting edge, starting from the Bohrrohrwandung, in particular radially, extends to the Bohrrohrachse. According to the invention, the main cutting edge is arranged and dimensioned such that, when rotating about the longitudinal axis of the drill pipe, it passes over part of the cross-sectional area of the conveying screw and preferably also of the drill pipe. For a particularly high cutting performance with good distribution of forces according to the invention preferably at least two main cutting edges are provided, which may be arranged in particular symmetrically with respect to the Bohrrohrachse.

It is particularly advantageous that the screw conveyor is rotated at a higher speed than the drill pipe with the main cutting edge. Such an operation is particularly suitable in the presence of coarse gravel. A high speed of the screw conveyor has the consequence that relatively high centrifugal forces act on the individual soil grains, which in turn can result in that the soil material is conveyed by the screw conveyor particularly quickly and effectively away from the main cutting edge upwards. Preferably, the speed of the screw conveyor is at least twice as large as the rotational speed of the drill pipe. The speed of the screw conveyor, for example, be up to 10 times greater than the speed of the drill pipe with the main cutting edge. In particular, the speed of the screw conveyor in the range 0.5 to 3 revolutions per second, preferably 1-2 revolutions per second, are. Suitably, drill pipe and screw conveyor are rotated in opposite directions - but they can also be rotated in the same direction.

Preferably, a continuous screw conveyor is used according to the invention, which is suitably longer than the intended drilling depth, so that it stands out of the borehole during the entire drilling. Preferably, the enveloping drill pipe is longer than the planned drilling depth. Conveniently, the auger for continuous removal of dissolved soil material to the surface during drilling is continuously rotated.

Furthermore, it is advantageous according to the invention that a filling material for forming a foundation element and / or wall element is introduced into the bore via a core tube of the screw conveyor. Preferably, after reaching a final depth, the drill pipe and the screw conveyor are withdrawn simultaneously, while the filling material, which preferably comprises concrete, is guided into the resulting cavity via the core tube.

The device according to the invention is characterized in that the main cutting edge is arranged on the drill pipe and is rotatable therewith.

The device according to the invention can be used for carrying out the method according to the invention, whereby the advantages explained in this connection can be achieved. The aspects of the invention described in connection with the method according to the invention can also be used in the device according to the invention, as well as the aspects described in connection with the device can be used in the method.

The screw conveyor is provided according to the invention with at least one coil. Since according to the invention in the cross section of the screw conveyor, in particular pending in the cross section of the helix Soil material is at least partially solved by the drill pipe arranged on the main cutting edge, no release tool must be provided on the coil; it only serves for transport and suitably comes into contact with soil material only when this soil material has already been released from the main cutting edge. The helix is preferably set back relative to the front side of the drill pipe into the interior of the drill pipe.

In principle, it can be provided according to the invention to deliver the screw conveyor of any cutting function and to provide the at least one main cutting edge so that it sweeps over the entire cross section of the screw conveyor during rotation. However, it may also be advantageous that at least one centering blade is provided on the screw conveyor, which projects in particular axially over the main cutting edge. In this case, the auger via the centering in addition to the main cutting also exerts a certain cutting function in the cross section of the screw conveyor. Preferably, the centering is non-rotatably mounted on the screw conveyor. The swept by the centering blade upon rotation of the screw conveyor cutting surface is suitably smaller than the swept by the main cutting edge upon rotation of the drill pipe cutting surface. The centering cutting, for example, have a plurality of teeth.

Furthermore, it is advantageous that at least one further cutting tool is arranged on the end face of the drill pipe at the circumference of the pipe. As a result, in addition to the main cutting edge on the drill pipe, a ring cutting edge can be formed, which releases soil material protruding from the drill pipe casing and facilitates axial sinking of the drill pipe. The further cutting tool can be designed in particular as a tooth.

A structurally particularly simple device is given by the fact that in a end region of the drill pipe, in particular in the pipe cross-section, a tool holder is arranged, on which the main cutting edge is arranged. The tool holder may, for example, have a plate which closes off the drill pipe on the front side. However, the tool holder can also be set back relative to the end face of the drill pipe into the drill pipe interior or stand out of the drill pipe. Suitably, at least one opening for the passage of processed soil material into the tube interior is provided on the tool holder.

Furthermore, it is advantageous according to the invention that at least one closure element is provided for closing the opening. This makes it possible to close the opening when pulling the drill pipe, so that processed and located in the drill pipe soil material can not get back into the hole. The closure member is preferably rotatable relative to the drill pipe and the opening about the longitudinal axis of the drill pipe.

The closure element may, for example, be non-rotatably connected to the conveyor screw. In this case, by rotation of the screw conveyor relative to the drill pipe, the opening can be opened and closed again. The closure element can also be connected non-rotatably to the main cutting edge.

For a particularly simple construction, it is advantageous that the main cutting edge is rotatably mounted on the drill pipe. But it can also be provided that the main cutting edge is rotatable relative to the drill pipe and that limiting means, in particular stops, but also locking bolts or locking pawls, which may be mechanically and / or hydraulically triggered, for example, or similar, are provided, which limit a rotation angle of the main cutting relative to the drill pipe. According to this embodiment, the main cutting edge can move with respect to the drill pipe within a certain predetermined angular range. The main cutting edge is taken by the rotating drill pipe only when it has encountered directly or indirectly against one or more attacks on the drill pipe. For actuating the locking bolts, locking pawls or other locking devices drive means may be provided.

This embodiment is particularly advantageous when the main cutting edge and closure element are rotatably connected. In this case, by rotating the main cutting edge together with the closure element relative to the drill pipe, the opening can be released or closed. In particular, for this purpose, the main cutting edge can be placed on the upcoming soil and the drill pipe to be rotated a piece, the main cutting edge with the closure element due to the friction at the bottom remains. Preferably, the stops are arranged to hold the closure element in a release position upon release of the drill pipe in the cutting direction of the main cutting edge in which the opening is released and, when rotated counter to the cutting direction, hold the closure element in a closed position in which it covers the opening , For the same purpose, the limiting means may additionally or alternatively to the attacks also bolts, pawls and / or locks.

A further advantageous development of the invention consists in that the main cutting edge is arranged on a retaining plate running obliquely to the longitudinal axis of the drill pipe, in particular on a helix. Due to its inclination, the holding plate, which may also be referred to as a cutting bar or conveyor plate, suitably from the main cutting edge processed soil material upon rotation of drill pipe and main cutting axially towards the inside of the tube to feed auger out, which takes over the further transport of the soil material. Preferably, the retaining plate is arranged so that it encloses an angle in the range between 10 ° and 80 ° with the bottom of the hole and / or extending perpendicular to the longitudinal axis of the drill pipe horizontal. If the main cutting edge is provided on a helix, the main cutting edge can be made helical. But it may also be formed, for example, substantially radially to the longitudinal axis of the drill pipe at the end of the helix. Preferably, the helix is formed as a progressive helix with an outer diameter decreasing towards the helix tip and / or a pitch increasing toward the helix tip. In this case, the main cutting edge can form a helix of variable diameter. In particular, the main cutting edge can be designed so that it passes over a conical or otherwise convex surface during rotation.

For a particularly efficient material transport from the main cutting edge through the opening of the tool holder into the tube interior to the screw conveyor, it is advantageous that the holding plate is arranged in the region of the opening on the tool holder and preferably forms an acute angle with the end face of the opening. In this case, the support plate may convey soil material through the opening upon rotation.

A further advantageous embodiment of the invention is that the screw conveyor has a core tube for introducing a filling material into the bore, and that at least one outlet opening for the filling material is provided on the core tube. Preferably, the core tube projects axially beyond the drill pipe on the end face of the drill pipe provided with the main cutting edge. In this case, the outlet opening suitably offset axially outwardly of the drill pipe. However, the outlet opening for the filling material can also be located in core tube areas within the drill pipe. In this case, the filling material can pass through an opening in the core tube and / or in the tool holder, which is identified in the figures, for example by the reference numeral 11, and which can also be used for the passage of processed soil material into the tube interior, from the tube interior to the outside reach. The outlet opening may be provided, for example, laterally and / or frontally on the core tube. Preferably, a centering edge is attached to the end face of the core tube.

A particularly high quality of the foundation and / or wall element formed during the filling of the bore can be achieved by providing a closure device for closing the outlet opening. The closure device is preferably designed such that the outlet opening is closable by placing the core tube at the bottom of the hole. By way of example, the closure device can have a punch, which can be axially displaceably arranged in the interior of the core tube, and is formed on the end face with a contact surface for the adjacent base. When drilling this punch is suitably inserted from the upcoming soil material in the core tube, whereby a laterally arranged on the tube soul outlet can be closed. If the auger, however, pulled, so the punch, for example, due to pressure or gravity effect or by means of a return device, axially move out of the tube and thus release the outlet opening. Instead of a stamper arranged in the interior of the core tube, the closure device can also have a sleeve which can be displaced axially on the outside of the tube.

A particularly reliable device is obtained in that the conveyor screw is rotatably mounted on the drill pipe in the end region of the drill pipe. For example, a rotary bearing can be provided on the tool holder of the drill pipe, in which the core tube of the screw conveyor is received. In particular, the end region can be understood as the region facing the bottom on which the cutting edges are arranged. Due to the end storage of the auger on the bottom tube, the screw conveyor is centered in the bottom tube, so that you can work with extra long augers without the risk that the auger undesirably comes into contact with the inner wall of the drill pipe.

According to a further preferred embodiment, the main cutting edge on a Kaliberschneidebereich, which suitably extends at least approximately arcuately around the tube axis around. Such a caliber cutting area can facilitate the penetration of the drill pipe into the ground and improve the smoothness.

Fig. 1

eine teilweise geschnittene Seitenansicht eines ersten Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung;

Fig. 2

eine Ansicht der Vorrichtung der Fig. 1 von unten;

Fig. 3

eine teilweise geschnittene Seitenansicht eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung;

Fig. 4

teilweise geschnittene Seitenansichten eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung in verschiedenen Betriebszuständen;

Fig. 5

eine teilweise geschnittene Seitenansicht (oben) und eine Ansicht von unten (unten) eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung;

Fig. 6

eine perspektivische Ansicht eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung;

Fig. 7 bis 14

perspektivische Ansichten weiterer Ausführungsbeispiele erfindungsgemäßer Vorrichtungen.

The invention is explained in more detail below with reference to preferred application examples, which are shown schematically in the figures. In the figures show:

Fig. 1

a partially sectioned side view of a first embodiment of a device according to the invention;

Fig. 2

a view of the device of Fig. 1 from underneath;

Fig. 3

a partially sectioned side view of another embodiment of a device according to the invention;

Fig. 4

partially sectioned side views of another embodiment of a device according to the invention in different operating states;

Fig. 5

a partially sectioned side view (top) and a bottom view (bottom) of another embodiment of a device according to the invention;

Fig. 6

a perspective view of another embodiment of a device according to the invention;

Fig. 7 to 14

perspective views of further embodiments of inventive devices.

In the FIGS. 6 to 14 is the sake of clarity, the screw conveyor not shown. Equally acting elements are identified in all figures with the same reference numerals.

A first embodiment of a device according to the invention for creating a bore in the ground is in the Figures 1 and 2 shown. The device has a rotatably drivable drill pipe 1, in which a screw conveyor 2 is arranged coaxially. The screw conveyor 2 has a core tube 8, on the outside of which a helix 9 runs longitudinally.

At the borehole end of the drill pipe 1 designed as a cover plate tool holder 13 is provided, which closes the drill pipe 1 partially. The tool holder 13 extends in sections from the wall of the drill pipe 1 radially to the longitudinal axis of the drill pipe 1. In the tool holder 13, two circular sector-like openings 11, 11 'are formed, which allow material transport through the tool holder 13 into the Bohrrohrinnere and the conveying area of the screw conveyor 2 ,

With respect to the longitudinal axis of the drill pipe 1 diametrically opposite, two obliquely extending holding plates 3, 3 'are arranged on the side of the tool holder 13 facing away from the pipe. At these holding plates 3, 3 'are each a plurality of teeth 4 are provided, each forming a main cutting edge 50, 50'. The teeth 4 may be, for example, flat teeth, round shank bits and / or studs. In particular, they may have a carbide finish.

About the holding plates 3, 3 'and the tool holder 13, the two main cutting edges 50, 50' rotatably connected to the drill pipe 1. Due to their frontal arrangement with respect to the screw conveyor 2 can be solved by turning the drill pipe 1 by means of the main cutting edges 50, 50 'in the conveyor section of the screw conveyor 2 pending soil. The dissolved soil material is taken up by the retaining plates 3, 3 'running obliquely to the horizontal and, upon further rotation of the drill pipe 1, is conveyed through the openings 11, 11' into the conveying region of the conveying screw 2. So that the dissolved soil material is taken up particularly reliably by the helix 9, it may be expedient to carry out this helix 9 in the end-side inlet region with smooth, in particular radially and / or horizontally extending edges.

In the tool holder 13, a recess 10 is provided centrally with respect to the drill pipe 1 through which the core tube 8 of the screw conveyor 2 passes. In this recess 10, the screw conveyor 2 is rotatably mounted on her soul tube 8 on the drill pipe 1, for which purpose may be provided on the recess 10, for example, a sliding bearing or a rolling bearing. At the front side, a centering blade 5 is arranged on the end of the core tube 8 protruding through the recess 10. This centering blade 5 protrudes axially beyond the main cutting edges 50, 50 'and is in rotationally fixed connection with the conveying screw 2. By means of the centering cutting edge 5, which is in Fig. 2 For the sake of clarity, as well as the core tube 8 is not shown, in the cross section of the core tube 8 pending soil material can be solved by rotation of the screw conveyor 2.

In the over the tool holder 13 protruding end portion of the core tube 8, an outlet opening 7 is laterally provided in the tube wall. Additionally or alternatively, an outlet opening may also be provided on the end of the tube 8. Through the core tube 8, a filler material can be introduced into the resulting cavity when the screw conveyor 2 and the drill pipe 1 are drawn, with the filler material emerging from the tube 8 through the outlet opening 7. In a further embodiment, the filling material can be introduced through the recess 10 into the resulting cavity.

Front side of the drill pipe further, designed as teeth cutting tools 6 are arranged on the pipe jacket. These form a ring cutting edge, which works below the drill pipe 1 pending soil material. The cutting tools 6 may also be formed as studs or chisels.

A further embodiment of a device according to the invention is in Fig. 3 shown. This in Fig. 3 illustrated embodiment differs from the embodiment of Figures 1 and 2 essentially in that in addition to the continuous helix 9 in the lower region of the screw conveyor 2, a second helix 30 is arranged.

A further embodiment of a device according to the invention is in Fig. 4 shown in two operating states. The left picture shows the state when drilling the device, the right picture shows the state when pulling the device.

According to the embodiment of the Fig. 4 the core tube 8 has on its end a sleeve-like punch 70, which is mounted axially displaceably in the interior of the adjacent core tube section. The outlet opening 7 is provided on the side wall of the punch 70. Front side of the punch 70, the centering blade 5 is arranged.

At the in Fig. 4 On the left shown drilling operation, the screw conveyor 2 together with the core tube 8 is pressed axially against the upcoming soil. The resulting reaction forces hold the centering blade 5 resting on the bottom together with the punch 70 in an upper position in which the punch 70 is inserted into the adjacent core tube section and the outlet opening 7 formed on the punch 70 faces the wall of the adjacent core tube section and is therefore closed. In this way, the risk can be reduced that soil material penetrates into the interior of the core tube 8 and this clogged.

At the in Fig. 4 Pulling process shown on the right is the punch 70 with the centering 5 lifted off the ground. Thus, the punch 70 can be moved out of the core tube 8, which can be effected for example by gravity, by a spring-actuated reset means and / or by acting on the interior of the core tube 8 with a pressure. The axial displacement of the punch 70 from the core tube 8 can be limited for example by a stop. In the in Fig. 4 right pushed out state of the punch 70, the outlet opening 7 is axially offset from the wall of the adjacent core tube section and thus released, so that filling material from the core tube 8 can get into the environment.

A further embodiment of a device according to the invention is in Fig. 5 shown. In contrast to the embodiment of Fig. 1 are the embodiment of the Fig. 5 Closing elements 15, 15 'for closing the openings 11, 11' of the tool holder 13 are provided. These closure elements 15, 15 'are rotatably connected to the screw conveyor 2. By relative rotation of the screw conveyor 2 relative to the drill pipe 1, the closure elements 15, 15 'between a closed position in which they cover the openings 11, 11', and an opening position in which they are laterally offset with respect to the openings 11, 11 'are arranged and release them. Fig. 5 shows the closure elements 15, 15 'in an intermediate position in which they only partially cover the openings 11, 11'. According to the embodiment of the Fig. 5 the closure elements 15, 15 'are formed as radially extending plates, which are arranged at the ends of the two coils 9 and 30, respectively.

Suitably, the apertures 11, 11 'are closed upon pulling the drill pipe 1 so that soil material in the drill pipe 1 can not fall down into the resulting cavity and / or fill material leaving the hearth tube 8, e.g. Concrete, can not penetrate into the drill pipe 1. In particular, it can be prevented that soil material from the drill pipe 1 can get into introduced filling material, where it could lead to undesirable inhomogeneities. Closing the openings 11, 11 'during pulling can be advantageous in particular when drilling in mobile floors. For example, it can be provided that the closure elements 15, 15 'are first brought into the closed position by turning the screw conveyor 2 relative to the drill pipe 1 and the screw conveyor 2 and the drill pipe 1 are then pulled without further rotation. But it is also possible to rotate the drill pipe 1 and the screw conveyor 2 when pulling at the same rotational speed and the same direction of rotation, whereby the closure elements 15, 15 'remain in the closed position.

A further embodiment of a device according to the invention is in Fig. 6 shown. This figure shows an advantageous arrangement of the holding plates 3, 3 'on the tool holder 13.

According to the embodiment of the Fig. 6 are the holding plates 3, 3 'following the openings 11, 11' provided on the tool holder 13 so that they conveyed through rotation processed soil material axially to the drill pipe 1 and through the openings 11, 11 '. For this purpose, the holding plates 3, 3 'suitably form an acute angle with the end faces of the adjacent openings 11, 11'.

With the pending floor include the holding plates 3, 3 'an angle of inclination α, which is suitably depending on the type of soil between 10 ° and 80 °. About this angle α is determined whether the soil is peeled off or is solved mainly by pressing and stirring.

Another embodiment of a device according to the invention is made Fig. 7 out. According to the embodiment of the Fig. 7 the main cutting edge 50 is arranged on the end side on a helix 16, which is connected in a rotationally fixed manner to the drill pipe 1 via the tool holder 13. The helix 16 ensures a particularly reliable transport of processed soil material into the drill pipe 1 to the screw conveyor.

In addition to an approximately radially extending cutting area, the main cutting edge 50 of the embodiment of Fig. 7 Also, a caliber cutting portion 18 which extends around the longitudinal axis of the drill pipe 1 around. Both in the radially extending cutting area and in the caliber cutting area 18 individual teeth are arranged on the main cutting edge 50.

The helix 16 extends around a pipe socket 23 which projects axially from the tool holder 13. This pipe socket 23, for example, as a bearing sleeve for in Fig. 7 not shown soul tube of the screw conveyor serve. Front side of the pipe socket 23, a centering blade 5 is arranged, which is preferably rotatably arranged in the illustrated embodiment with respect to the pipe socket 23 on the core tube. In principle, however, the centering blade 5 can also be provided in a rotationally fixed manner on the pipe socket 23, in which case it represents a further main cutting edge. The centering blade 5 is formed by a plurality of teeth.

A further embodiment of a device according to the invention is in Fig. 8 shown. The device of Fig. 8 has a closure element 20 with which the opening 11 in the tool holder 13 can be covered. This closure element 20 is designed as a cover plate, which is arranged on the side facing away from the drill pipe inside of the tool holder 13. The closure element 20 is rotatably mounted on the tool holder 13 relative to the drill pipe 1, for example via a roller bearing or a plain bearing. On the rotatable closure element 20, the main cutting edge 50 is fixed.

To close the opening 11, the drill pipe 1 is retracted into the ground, so that the main cutting edge 50 acts on the upcoming ground. Then the drill pipe 1 is rotated. However, the rotation is not understood by the closure element 20 due to the engagement of the main cutting edge 50 in the upcoming soil and the resulting friction, so that a relative movement between the closure element 20 and the drill pipe 1 adjusts with its opening 11. This movement can be maintained until the opening 11 is covered as desired by the closure member 20 or is released.

In order to rotatably couple the rotatably mounted main cutting edge 50 for a drilling operation with the drill pipe 1, are in the embodiment of the Fig. 8 not shown locking means provided, which can be controlled remotely, in particular from the earth's surface, opened or closed. The locking means may comprise, for example, pawls and / or bolts.

The closure element 20 is formed as a circular segment-like plate, which is formed on its side facing the interior of the drill pipe 1 side planar. The opposite, raw material facing away from the end face of the tool holder 13 is also formed planar. In this way it can be ensured that during operation of the closure element 20 comparatively little soil material passes between the closure element 20 and the tool holder 13 and thus the risk of jamming and wear is reduced.

In the embodiment of Fig. 8 the main cutting edge 50 forming teeth 4 are arranged obliquely directly on the cover-like closure element 20.

The recess 10 for the passage of in Fig. 8 Not shown soul tube 8 extends through the tool holder 13 and the thereto rotatably arranged closure element 20 therethrough. It makes it possible, even with the opening closed, to introduce filling material at the front side of the drill pipe 1 into the cavity created during drawing.

A further embodiment of a device according to the invention is in Fig. 9 shown. As in the embodiment of Fig. 8 is also in the embodiment of Fig. 9 provided on the front side of the tool holder 13 a rotatable relative to the tool holder 13 and the drill pipe 1, designed as a lid closing element 20, on which the main cutting edge 50 is arranged. In addition, in the embodiment of the Fig. 9 on the tool holder 13 stops 24, 25 are provided, which limit the angle of rotation of the closure element 20 relative to the tool holder 13 and the drill pipe 1.

In the embodiment of Fig. 9 Opening and closing of the opening 11 by the closure element 20 is likewise effected by turning the drill pipe 1, wherein the closure element 20 does not follow this rotation due to the friction with the surrounding floor and consequently a relative movement between closure element 20 and the opening 11 sets. Due to the stops 24, 25, however, a rotation of the closure element 20 with the main cutting edge 50 with respect to the drill pipe 1 is possible only in a limited angular range. If this angle range is exceeded, the closure element 20 strikes against one of the stops 24, 25 and is taken along by the drill pipe 1. The main cutting edge 50 then follows the rotation of the drill pipe 1 and can work off existing soil material. The stops 24, 25 are arranged so that they hold the closure element upon rotation of the drill pipe 1 in the cutting direction of the main cutting edge 50 in an open position in which the opening 11 is released, and on rotation opposite to the cutting direction of the main cutting edge 50 in a closed position the opening 11 is covered by the closure element 20.

In the illustrated embodiment, the stops 24, 25 are provided on the tool holder 13. Additionally or alternatively, stops may be arranged on the drill pipe 1 and / or on the closure element 20.

A further embodiment of a device according to the invention with a closure element 20 for covering the opening 11 is shown in FIG Fig. 10 shown. In contrast to the embodiments of the FIGS. 8 and 9 is in the embodiment of Fig. 10 the main cutting edge 50 is not formed directly on the plate-shaped closure element 20. Rather, a coil 16 is rotatably provided on the closure element 20, at the end of the main cutting edge 50 is formed. Helix 16 and main cutting edge 50 are analogous to the embodiment of Fig. 7 educated. A limitation of the angle of rotation of the closure element 20 may be effected by means not shown locking means and / or by stops also not shown.

As in the embodiment of Fig. 7 is also in the embodiment of Fig. 10 the end face of the device a pipe socket 23 'is provided, around which the helix 16 extends around. In the embodiment of Fig. 10 the pipe socket 23 'is arranged on the closure element 20. In the interior of the pipe socket 23 ', the not shown soul tube of the screw conveyor is mounted. Laterally on the pipe socket 23, an outlet opening 19 is provided for discharging filler material from the core tube. The outlet opening 19 may suitably be opened or closed by axially displacing the core tube which projects into the pipe socket 23 'with respect to the drill pipe 1 and thus the pipe socket 23'.

Front side of the pipe socket 23 'is in the illustrated Ausführungsbeispi: el a pilot blade 50 "arranged, which also forms a main cutting edge.

FIGS. 11 to 13 show further embodiments of inventive devices in which two spiral-like, designed as progressive cutting main cutting edges 50, 50 'are provided. These progressive cutting edges 50, 50 'are formed by teeth 4 arranged along a progressive helix 26.

In the embodiment of Fig. 12 is a rotatable relative to the drill pipe 1 closure element 20 for closing the opening 11 is provided. At this closure element 20, an additional, linearly executed main cutting edge 50 '''is arranged at the edge of a passage opening.

In the embodiment of Fig. 13 is in the central axis of the helix 26 and the drill pipe 1, an additional main cutting edge 50 '' arranged, which is designed as a pilot cutting edge.

A further embodiment of a device according to the invention is in Fig. 14 shown. In this embodiment, the main cutting edges 50, 50 'are formed on inclined plates 33.

Claims (13)

1. Method for producing a borehole in the soil, in which a drill pipe (1) and a conveyor screw (2) arranged inside the drill pipe (1) are set into rotation and introduced into the soil, and
   in which outcropping soil material is loosen by means of at least one main cutting edge (50), which is positioned axially in front of the conveyor screw (2) and is conveyed away by means of the conveyor screw (2) in the inside of the drill pipe (1),
   characterized in that
   the main cutting edge (50) is rotated together with the drill pipe (1) around a drill axis, wherein the main cutting edge (50) is arranged on the drill pipe (1) and extends toward the drill axis, so that the main cutting edge (50) during rotation moves over a part of the cross-section surface of the conveyor screw (2).
2. Method according to claim 1,
   characterized in that
   the drill pipe (1) and the conveyor screw (2) are controlled independently of each other with regard to the rotational speed and/or the direction of rotation.
3. Method according to any one of claims 1 or 2,
   characterized in that
   the conveyor screw (2) is rotated at a higher rotational speed than the drill pipe (1) with the main cutting edge (50), wherein the rotational speed of the conveyor screw (2) lying preferably in the range of 0.5 - 3 revolutions per second.
4. Method according to any one of claims 1 to 3,
   characterized in that
   via a core pipe (8) of the conveyor screw (2) a filling material is introduced into the borehole in order to produce a foundation member.
5. Device for producing a borehole in the soil for carrying out the method according to any one of claims 1 to 4, comprising

   - a drill pipe (1),

   - a conveyor screw (2) arranged inside the drill pipe (1), and

   - at least one main cutting edge (50), which is positioned axially in front of the conveyor screw (2) for stripping soil material,

   characterized in that
   the main cutting edge (50) is arranged on the drill pipe (1) and can be rotated therewith around a drill axis, wherein the main cutting edge (50) extends beginning from a wall of the drill pipe (1) toward the drill axis.
6. Device according to claim 5,
   characterized in that

   - on the conveyor screw (2) at least one centering cutting edge is provided which projects from the main cutting edge (50) in particular in axial direction and/or

   - at least one further cutting tool (6) is arranged at the front face of the drill pipe (1) on the circumference thereof.
7. Device according to any one of claims 5 or 6,
   characterized in that

   - in an end portion of the drill pipe (1) a tool holder (13) is arranged, on which the main cutting edge (50) is arranged, with

   - at least one opening (11) being preferably provided on the tool holder (13) for the passage of stripped soil material into the inside of the pipe.
8. Device according to claim 7,
   characterized in that
   at least one closing member (15, 20) is provided for closing the opening (11), which is connected in a rotationally fixed manner with the conveyor screw (2) or the main cutting edge (50).
9. Device according to any one of claims 5 to 8,
   characterized in that
   the main cutting edge (50) is rotatable relative to the drill pipe (1) and limiting means, in particular stops (24, 25), locking bolts and/or locking pawls or the like, are provided which limits an angle of rotation of the main cutting edge (50) relative to the drill pipe (1).
10. Device according to any one of claims 5 to 9,
    characterized in that
    the main cutting edge (50) is arranged on a holding plate (3) extending in an oblique manner to the longitudinal axis of the drill pipe (1), in particular on a helix (16, 26).
11. Device according to claim 10,
    characterized in that
    the holding plate (3) is arranged on the tool holder (13) in the area of the opening (11) and preferably includes an acute angle with the front face of the opening (11).
12. Device according to any one of claims 5 to 11,
    characterized in that

    - the conveyor screw (2) has a core pipe (8) for introducing a filling material into the borehole,

    - on the core pipe (8) at least one outlet opening (7, 19) for the filling material is provided and

    - a closing device is provided for closing the outlet opening (7).
13. Device according to any one of claims 5 to 12,
    characterized in that
    the conveyor screw (2) is rotatably supported on the drill pipe (1) in the end portion of the drill pipe (1).

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